Method of making crowns, bridge works, post crowns, dentures, denture plates, and inlays, and an equipment therefor

ABSTRACT

The present invention related to crowns, bridge works, post crowns, denture plates and various inlay members composed of a polymeric material selected from a chlorotrifluoroethylene homopolymer or copolymer thereof and a vinylidenfluoride homopolymer or copolymer thereof. Examples of copolymers which may be used to produce the former copolymers are those produced from a chlorotrifluoroethylene monomer and a vinylidenfluoride or vinylfluoride monomer, and examples of the latter copolymers are those produced from vinylidenfluoride and tetrafluoroethylene or hexafluoropropene. The above denture materials may also contain pigments or reinforcing materials therein. Also the denture materials may be covered with a film of a solution of the aforementioned polymeric materials and pigments to form a coating on the denture plates, etc.

June 29. 1971 Filed June 5, 1968 .2 Sheets-Sheet l l. 26 {i 24 l? 21 18mm 1 I u Ii 'i i SHIZUO TANIGIJCHI,

INVENTOR 1 BY L wp k June 29. 1971 SH uo NIGUCHI 3,589,010

ME D OF MAK CR0 5, BRIDGE WOR POST OW DE URES, E PLATES, ND

IN S, AN E NT THEREFOR Filed June 5, 1968 2 Sheets-Sheet 2 smzuoTAMIGLICHI INVENTUR BY whim. XML

ATTORNEYfi United States Patent 3,589,010 METHOD OF MAKING CROWNS,BRIDGE WORKS, POST CROWNS, DENTURES, DENTURE PLATES, AND INLAYS, AND ANEQUIPMENT THEREFOR Shizuo Taniguchi, Osaka, Japan, assignor offractional part interest to Daikin Kogyo Co., Ltd., Osaka, JapanContinuation-impart of application Ser. No. 518,635, Jan. 4, 1966. Thisapplication June 5, 1968, Ser. No. 734,681 Claims priority, applicationJapan, Jan. 1, 1965, 40/3,203; Sept. 22, 1965, 40/57,985 Int. Cl. A61c13/00 US. Cl. 32-2 6 Claims ABSTRACT OF THE DISCLOSURE The presentinvention relates to crowns, bridge works, post crowns, denture platesand various inlay members composed of a polymeric material selected froma chlorotrifluoroethylene homopolymer or copolymer thereof and avinylidenfluoride homopolymer or copolymer thereof. Examples ofcopolymers which may be used to produce the former copolymers are thoseproduced from a chlorotrifluorethylene monomer and a vinylidenfiuorideor vinylfluoride monomer, and examples of the latter copolymers arethose produced from vinylidenfluoride and tetrafiuoroethylene orhexafluoropropene. The above denture materials may also contain pigmentsor reinforcing materials therein. Also the denture materials may becovered with a film of a solution of the aforementioned polymericmaterials and pigments to form a coating on the denture plates, etc.

This application is a continuation-in-part-of my pending applicationSer. No. 518,635 filed Jan. 4, 1966.

This invention relates to a method of making crowns, bridge work, postcrowns, dentures, denture plates, and inlays, and an apparatus therefor.The invention also relates to the crowns, bridge Works, post crowns,dentures, and denture plates, and inlays made by said method.

A primary feature of this invention lies in the molding of granules,pellets, or other finely divided form of a polymeric material selectedfrom the group consisting of chlorotrifluroethylene homopolymer andcopolymer thereof with copolymerizable monomer, and vinylidenfluoridehomopolymer and copolymer thereof with copolymerizable monomer, througha mold into the desired shape. The former copolymerizable monomer isto'be selected from the group consisting of vinylidenfiuoride,vinylfioride, tetrafluroethylene and hexafiuropropene, and also thelatter copolymerizable monomer is to be selected from the groupconsisting of vinylfiuoride, tetrafiuroethylone and hexafiuropropene.

Another feature of the invention is that a pressureresponsive sealedcontainer holding said polymeric material is positioned in such a mannerthat its lower end comes in close contact with a mold, with the upperend of said container being positioned immediately under the lower endof a pressing rod of a pressing mechanism, said sealed container beingmade of alminum or the like material and being heated by a heatingdevice.

In another aspect, the present invention is concerned with the crown,bridge work, post crown, denture, denture plate, and inlay made fromsaid resinous material by means of the above-mentioned method andapparatus.

In accordance with the convenitonal dental procedure, porcelain oracrylic material is formed in to various individual shapes, among whichthe one which looks like the clients natural tooth is chosen for thedental surgery ice scheduled for the same client. However, this surgerydepends on the so-called crown and bridge arts which involve metal crownlining, jointing, and other technics using metals. 'It is alsoconventional practice to secure a pattern of the natural tooth and gumin the mouth, prepare a split mold from said pattern, fill manually anapproximate denture into said split mold, plant the same in a dentureplate, lock it in position, and, finally, boil or other-wise heat thesame for prolonged time until it is coagulated in place.

However, porcelain dentes, which may be sufliciently hard, are brittleand vulnerable to directional cracking. Furthermore, this type ofdentes. tends to emit a louder biting sound or bouxism because it isgenerally manufactured in the same manner as ordinary householdporcelain articles, in addition, further said type of dentes is too muchdiflicult to be colored with any desired color.

Still another disadvantage of such an artificial tooth is itspossibility of damaging the mating natural tooth. On the other hand, thetooth of acrylic resin is not as hard as desired, let alone its lowdensity which makes the dentes quite liable to become worn out as theclient brushes his teeth or ingests foods.

I have long been engaged in studies in the hope of improving theabove-mentioned disadvantages of the conventional crowns, bridge works,dentures, denture plates, and inlay, and have ultimately succeeded inthe formation in a very short period of time of crowns, bridge works,post-crowns, dentures, and denture plates which resemble closely naturalteeth in surface hardness, smoothness, luster, and appearance, are freefrom directional cracking, possess a high degree of abrasion resistance,and are free from bouxism.

In one preferred mode of embodiment of the principle of this invention,a sealed aluminum container capable of contraction under pressure or thelike container is charged with pellets, granules, or the other finelydivided form of a polymeric material selected from the group consistingof chlorotrifluorethylene homopolymer and copolymer thereof withcopolymerizable monomer, and vinylidenfluoride homopolymer and copolymerthereof with copolymerizable monomer, and if desired, a mixture of saidpolymeric material, pigment which may be titanium oxide, cadmium yellow,cadmium red, carbon black, zinc oxide or barium sulfate and/ orinorganic reinforcing material which may be glass fiber or mineralfiber. After it is sealed, the container is heated in an electricfurnace at 350 C. until the contents are molten, whereupon the lower endof said container is immediately brought into contact with an openingprovided in a collapsible mold case containing a suitable mold or molds.Thus, when the upper end of said container is pressed by the pressingrod of a pressing system, the bottom wall of said container which, asabove, is held in intimate contact with said mold case is burst open inthe manner of an explosion, whereby creating an injection hole therein.Through this hole or opening, the molten mass flows out of saidcontainer under pressure into the metal mold contained in said case.This procedure gives rise to excellent crowns, bridge works,post-crowns, dentures, denture plates, or inlay, in an efiicient manner.More specifically, the starting material pellets or granules may beprepared in the following examples.

EXAMPLE 1 Chlorotrifiuoroethylene homopolymer (white powdery material)of which ZST value provided in ASTM D 143058 T is 420 secs. may beheated in said container at 310 C. for 10 mins. under elevated pressureto produce crowns and other products.

The physical properties of the final products are as follows:

Hardness: Shore Durometer D 84.

In addition, further said shore durometer may increase up to D 90 bymeans of the further annealing treatment thereof 180 C. x 1 hr.

It was registered that no discoloration had happened for 2 years on theproducts applied to 1000 persons.

EXAMPLE 2 Chlorotrifiuroethylene copolymer (white powdery material)containing 3% of Vinylidenfluoride of which ZST value provided in ASTM D143058 T is 250 secs. may be heated in said container at 290 C. formins. under elevated pressure to produce crowns and other products.

The physical properties of final products are as follows:

Hardness: Shore Durometer D 84.

In addition, further said shore durometer may increase D 88 by means ofthe further annealing treatment thereof 170 C. x 1 hr.

It was registered that no discoloration had happened for 2 years on theproducts applied to 1000 persons.

EXAMPLE 3 Vinylidenfluoride homopolymer of which intrinsic viscosity (1)at C. is 1.5 may be heated in the container at 290 C. for 10 mins. underelevated pressure to produce crowns and other products.

The physical properties of the final products are as follows:

Hardness: Shore Durometer D 83.

It was registered that no discoloration had happened for 12 months onthe products applied to 4 persons.

EXAMPLE 4 Vinylidenfluoride copolymer containing 5% of vinylfluoride ofwhich intrinsic viscosity (1) at 35 C. is 0.6 may be heated in thecontainer at 250 C. for 10 mins. under elevated pressure to producecrowns and other products.

The physical properties of the final products are as follows:

Hardness: Shore Durometer D 83.

It was registered that no discoloration had happened for 6 months on theproducts applied to 1 person.

EXAMPLE 5 When, as the polymeric material, is selectedchlorotrifluroethylene homopolymer of which ZST value provided in ASTM D143058 T is 420 secs., it may be blended with the aforesaid pigments asfollows:

Parts Chlorotrifl uroethylene homopolymer (white powdery material) 100Titanium oxide 0.08 Cadium yellow 0.0034 Cadium red 0.0032 Carbon black0.0003

Said mixture will be heated in said container at 310 C. for 10 mins.under elevated pressure to produce crowns and other products.

The physical properties of the final products are as follows:

Hardness: Shore Durometer D 85.

In addition, further said shore durometer may increase up to D 90 bymeans of the further annealing treatment thereof 180 C. x 1 hr.

As to the resulted advantage of the final products, we found anydiscoloration had never happened for 2 years on the products applied to1000 persons.

EXAMPLE 6 Chlorotrifluoroethylene copolymer containing 3% ofVinylidenfluoride, of which ZST value provided in ASTM D 143058 T is 250secs. may be blended with glass fiber (diameter thereof 10a and averagelength 50p.) and the underwritten pigments as follows:

Parts Chlorotrifluroethylene copolymer Glass fiber 1 Titanium oxide 0.08Cadium yellow 0.0034 Cadium red 0.0032

Carbon black 0.0003

Vinylidenfluoride homopolymer of which intrinsic vis- .cosity (r) at 35C. is 1.5 may be blended with the underwritten pigments as follows:

Parts Vinylidenfluoride homopolymer 100 Titanium oxide 0.08 Cadiumyellow 0.005 Cadium red 0.003 Carbon black 0.0003

Said mixture will -be heated in the container at 290 C. for 10 mins.under elevated pressure to produce crowns and other products.

The physical properties of the final products are as follows:

Hardness: Shore Durometer D 86.

It was registered that no discoloration had been happened for 12 monthson the products applied to 4 persons.

EXAMPLE 8 Vinylidenfluoride copolymer containing 5% of vinylfluoride, ofwhich intrinsic viscosity (-r) at 35 C. is 0.6 may be blended with theunderwritten pigments as follows:

Parts Vinylidenfluoride copolymer 100 Titanium oxide 0.08 Cadium yellow0.0034 Cadium red 0.0032 Carbon black 0.0003

Said mixture will be heated in the container at 250 C. for 10 mins.under elevated pressure to produce crowns and other products.

The physical properties of the final products are as follows:

Hardness: Shore Durometer D 83.

It was registered that no discoloration had been happened for 6 monthson the products applied to 1 person.

EXAMPLE 9 1 part of polychlorotrifiuroethylene of which ZST valueprovided in ASTM -D 143058 T is 420 secs. may be dissolved into 100parts of 2, 4-dichlorobenzotrifluoride, in addition, further 0.00003part of cadium yellow and 0.00003 part of cadium red are dispersed intosaid solution.

The resulted solution as shown in the above is to be applied (coated) tothe outer surface of each of final products made by means of treatmentas shown in said Example 1 or 2.

After said application, the products coated may be cured at 190 C. for10 mins., in such manner that the step for coloring them is to befinished.

EXAMPLE 10 1 part of polyvinylidenfluoride of which intrinsic viscosity(T) at 35C. is 1.5 may be dissolved into 100 parts of dimethylformamidefurther 0.00004 of cadium yellow and 0.00002 part of cadium red aredispersed into said solution.

The resulted solution as shown in the above is to be applied (coated) tothe outer surface of each of final products made by means of treatmentas shown in said Example 3 or 4.

After said application, the products coated may be cured at 170 C. for10 mins., in such manner that the step for coloring them is to befinished.

As shown in the above-written Examples and 6, it is very easy, in thepresent invention, to color crowns and others with any desired color.

Listed below are some of the chemical, physical and electricalproperties of crowns and others finally produced according to theaforesaid examples:

(1) Artificial crowns and other products according to the presentinvention are highly resistant to intraoral heat and the heat of thefood and drink ingested.

(2) The crovms and others manufactured according to the presentinvention are comparable to brass in feeling, and, when they must becorrected, may be easily processed by regular dental drills, cutters,and other instruments and finished by grinding and polishing.

(3) Translucent coloring is easy when materials are as thin as 3millimeters or less, and may be used for lining and coating purposes.Thus, the materials may be utilized for the purpose of repairing wornteeth.

(4) Hardness of each of crowns and others produced according to thepresent invention is shown as Shore Durometer -D 85, 90, 87, 89, 86 or83, respectively.

(5) Said crowns and others are highly resistant to discoloration thereoffor a long period.

('6) Said crowns and others are quite identical with natural teeth incolor, luster, smoothness, and all of them are extremely tough anddurable.

(7) And especially, in the present invention, unlike the conventionalporcelain dentures which make it necessary to bake and cut each dent, isprovided a useful means whereby a great many crowns and others may beeasily molded in a continuous manner. It also is a great advantage ofthe present invention that without employing such costly materials asgold, silver, platinum and, other alloys, crowns, bridge works, dentes,inlays, and other dental products of excellent quality may bemanufactured easily and at low cost.

In addition, further pellets prepared by admixing afiinitized finelydivided or short glass fiber with a plastisol of the above materials areeasy to handle and permit easy and accurate weighing of the materialsexpected to go into crowns or other products. Thus, the inventionprovides a means of making varieties of crowns and others which are notonly tough and resistant to abrasion, but also low in contraction andfree from bouxism. It is to be noticed that small amounts of inorganicreinforcing material may be incorporated in the molding compositionhereinbefore described.

Other features, effects, and advantages of the present invention willbecome apparent as the description proceeds, reference being had to theaccompanying drawings, in which:

FIG. 1 is a side-elevational view of the apparatus to be employed in themethod of this invention;

:FIG. 2 is a partial section, on exaggerated scale, showing theconnection between the split-mold case and the sealed container withinthe apparatus illustrated in FIG. 1;

FIG. 3 is a schematic view, explaining crowns for various teeth of thisinvention;

FIG. 4 is a schematic view, showing a primoris post crown of upper jawsof the invention;

FIG. 5 is a schematic view of a mandibular molar bridge work of theinvention;

FIG. 6 is a schematic view showing the artificial dentes of FIG. 5 asarranged tentatively for the preparation of a denture; and

FIG. 7 is a plan view of the dentes of FIG. 6 as mounted on a plate.

Referring, now, to FIG. 3, a single crown 1 is mounted on a natural dent2, while, as shown in FIG. 4, a primoris post crown 3 is mounted on anatural dent 4, with the root portion of said dent 4 remaining exposed.In FIG. 5, a bridge work 5 is connected with crowns 6 covering twoadjoining natural dentes 4 and 4. In FIG. 6, the left half of a dent fora denture plate is tentatively arranged, while FIG. 7 shows theartificial dentes mounted on a denture plate 7.

In FIGS. 1 and 2, an oil pressure molding mechanism 8 provides apressure gage 9, a base 10', a frame 11, a motor 12, a hydraulic system13, a pressing rod 14 of a pressing system and bars 15, 15. A metalsplit-mold case 16 is mounted on said base 10, and said metal split-moldcase 16 consists of upper and lower halves 17 and 17. The upper andlower openings of said case 16 are covered with top cover 18 of saidupper halve 17 and a bottom cover 19 of said lower halve 17. Said halves17 and 17' are removably connected with the lower and upper ends thereofthrough respective bolts 20, '20. In the center of said top cover 18 isprovided an orifice 21, and a plaster or metal mold 22 is contained insaid case 16. A required number of molds representing the dentesprimoris, molaris, etc., of a denture are set in said case 16. Analuminum container 23 or any other container capable of contractionunder pressure as described above is charged with pellets of theabovementioned resin composition. The container 23 is encased in anouter casing 24 which is provided with a handle 25. Container, in thisstate, is heated at the temperatures mentioned hereinbefore, andimmediately thereafter, a bottom wall 26 of said container 23 is broughtinto contact with the rim of said orifice 21 formed in said top cover18. Through said hydraulic system 13, the lower end of said rod 14 isbrought into con tact with a top wall 27 of said container through theupper opening of said case 1 6. As the rod 14 travels downward, the topwall 27 of said flexible container within said outer casing is pressed,whereupon the container is forced to shrink. The internal pressure builtup within said container in this manner causes a bottom wall 26 thereofto burst open thereby creating an opening in said bottom wall. Themolten composition is then forced out through said opening and saidorifice 21 into the molds 22 Within said case 16. In this manner, agreat number of crowns and other products are molded in one operation.It is also possible to obtain a complete denture plate carrying therequired dentes by forcing the material composition as above into ametal mold in which the finished artificial dentes prepared above havebeen properly arranged.

What I claim is:

1. A crown, bridge work, post crown, denture, denture plate and inlaymember, said member being comprised of a polymeric material selectedfrom the group consisting of a chlorotrifiuoroethylene homopolymer and acopolymer thereof with a copolymerizable monomer, and avinylidenfluoride homopolymer and copolymer thereof with acopolymerizable monomer; the former copolymerizable monomer beingselected from the group consisting of vinylidenfluoride, vinylfiuoride,tetrafiuroethylene and hexafluoropropene, and the latter copolymerizablemonomer being selected from the group consisting of vinylfiuoride,tetrafiuroethylene and hexafiuoropropene.

2. A crown, bridge work, post crown, denture, denture plate and inlaymember as claimed in claim 1, wherein said member is comprised of saidpolymeric material and a suitable pigment selected from the groupconsisting of titanium oxide, cadmium yellow, cadmium red, carbon black,zinc oxide and barium sulfate.

3. A crown, bridge work, post crown, denture, denture plate and inlaymember as claimed in claim 1, wherein said member is comprised of saidpolymeric material and a suitable inorganic reinforcing materialselected from the group consisting of glass fiber and mineral fiber inor without the presence of a suitable pigment selected from the groupconsisting of titanium oxide, cadmium yellow, cadmium red, carbon black,zinc oxide and barium sulfate.

4. A crown, bridge work, post crown, denture, denture plate and inlaymember as claimed in claim 1, wherein said member comprised of saidpolymeric material is covered with a film formed by coating on the outersurface thereof a solution of said polymeric material and a suitablepigment selected from the group consisting of titanium oxide, cadmiumyellow, cadmium red, carbon black, zinc oxide and barium sulfate.

I 5. A crown, bridge work, post crown, denture, denture plate and inlaymember as claimed in claim 2, wherein said member is comprised of saidpolymeric material and said pigment is covered with a film formed bycoating on.

the outer surface thereof a solution of said polymeric material and asuitable pigment selected from the group consisting of titanium oxide,cadmium yellow, cadmium red, carbon black, zinc oxide and bariumsulfate.

6. A crown, bridge work, post crovsm, denture, denture plate and inlaymember as claimed in claim 3, wherein said member comprised of saidpolymeric material and said inorganic reinforcing material is coveredwith a film formed by coating on the outer surface thereof a solution ofsaid polymeric material and a suitable pigment selected from the groupconsisting of titanium oxide, cadmium yellow, cadmium red, carbon black,zinc oxide and barium sulfate.

References Cited UNITED STATES PATENTS 3,084,436 4/ 1963 Landry 3223,244,684 4/1966 Teumac 26092.1 3,285,898 11/ 1966 MacKenzie 260-9233,356,649 12/1967 Wolf 260-73 ROBERT PESHOCK, Primary Examiner

